Fixing element and method for fixing insulation tracks or plates on a fixed substructure

ABSTRACT

The invention relates to a fixing element ( 1 ) for fixing insulation and scaling tracks on a fixed substructure. Said element comprises a screw ( 9 ) and a large washer ( 7 ) with a cylindrical extension ( 8 ). The screw ( 9 ) has two thread segments ( 13, 14 ), wherein one thread segment ( 13 ) interacts with the through hole in a reciprocal thread engagement located in a narrowed area ( 12 ) of the cylindrical extension ( 8 ). An axial relative movement of both parts can be achieved by reciprocally rotating the cylindrical extension ( 8 ) and the screw ( 9 ).

BACKGROUND OF THE INVENTION

The invention relates to a fastening element for attaching insulatingstrips or plates and possibly additional sealing strips to a solidsubstructure, consisting of a screw which is provided with a thread overat least a portion of the length of its shaft and has a screw head, anda large-area washer having a tubular extension, in which the extensionof the washer has, at least over a large portion of its length, aninternal cross-section sufficiently large for the rotatable receptionand for the axial displacement of the screw head and which is narrowedat its end region remote from the washer to permit passage of thescrew's shaft. The invention relates further to a method of attachinginsulating strips or plates and possibly other additional sealing stripsor bituminous underlayers to a solid substructure of thin concrete bymeans of a fastening element which consists of a screw and a large-areawasher having a tubular extension.

DESCRIPTION OF THE RELATED ART

Solutions are indeed known, in which the fastener is telescopicallyslidable within the tubular extension, so that a variation in overalllength can be achieved. However, such a construction is not desirable,especially for a roof structure in which the large-area washer is to bepressed against the top-most sealing strip.

Applications for attaching insulating and sealing strips to asubstructure of thin concrete or other materials, e.g. sheet metal andthe like, also exist in new construction, when a relatively thickinsulating strip is used. In such a case, too, the overall length of thefastening element formed by the fastener itself and the tubularextension of the large-area washer, desirably enables the compensationfor different overall thicknesses of the materials to be attached, overa relatively wide range. Especially for cases in which such compensationis desired, but the known telescope-like configuration of relativelyslidable fastener and tubular extension is not suitable, there wereheretofore no adequate solutions.

BRIEF SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a fasteningelement and a method of the kind described at the outset, by which largeattachment distances can be bridged by the use of a fastener and alarge-area washer with a tubular extension, which nevertheless enablesthe adequately forceful pressing of the large-area washer against thetopmost sealing or insulating strip.

This is accomplished in accordance with the invention by making theouter diameter of the screw shaft thread greater than the freepass-through opening of the narrowed region of the tubular extension,whereby the screw is in operative engagement with the narrowed region ofthe tubular extension through mutual threaded engagement, or else can bebrought into such engagement by rotating the screw into the pass-throughopening.

By these techniques embodying the invention, the washer with its tubularextension can be pushed into a correspondingly preformed hole in theentire structure, using a washer with a tubular extension of theavailable length. During screwing of the fastener into the substructure,the same simultaneously enters into operative engagement with thetubular extension over an appropriate thread section, so thattelescope-like axial displacement between fastener and tubular extensionis no longer possible. Thus the fastener and the washer with its tubularextension form an axially stable attaching element. However, because thefastener and the narrowed region of the tubular extension are in mutualthreaded engagement, the washer together with its tubular extension cansubsequently still be rotated—if that appears to be necessary—whereby,for example, the force pressing the large-area washer against the topside of the insulating or sealing strip can be increased. That is,through rotation of the large-area washer, the latter is drawn axiallyfurther toward the interior, depending upon the thread pitch of thefastener, or else the applied pressure can be reduced by reverserotation of the washer and with it the tubular extension, if thecompressing is too strong.

An advantageous embodiment provides that the screw is provided with athread over at least a substantial portion of the length of its shaft.By so doing, a large region can be used as the needed overall length ofthe attaching element, because the fastener can extend more or less farinto the tubular extension of the washer. What is important is only thata threaded region of the fastener is in threaded engagement with thenarrowed region at the free end of the tubular extension. For thatreason, for greatest possible utilization of the length of the fastenerand of the length of the tubular extension, it is desirable that thescrew be provided with a thread over the entire length of the shaft.

A further advantageous construction consists in providing twodifferently formed thread sections on the shaft of the screw. Thispermits accommodating the possibility that, in the substructure to whichthe entire structure is to be ultimately attached, there can be provideda thread which is suitable for the substructure and the optimum threadconfiguration can be provided in the region of threaded engagementbetween the screw and the narrowed portion of the tubular extension.

In this regard, it is preferred that the two thread sections on thescrew shaft have different diameters but the same thread pitch. Toachieve even better engagement, it may be appropriate to penetrate thesubstructure using a smaller outer diameter. This also makes itpossible, for example, that the first thread section of smaller diameterdoes not need to be threaded through the narrowed portion of the tubularextension. This is desirable especially for pre-mounting the fastener inthe tubular extension.

For special substructures, it may be desirable to make the smallerdiameter thread section at the free end of the screw shaftdouble-threaded. This also makes it possible to make the double-threadedpart of the threaded section with threads having different outerdiameters. Such a structural configuration is especially advantageousfor direct application to concrete.

A further desirable embodiment provides that, if there are two threadsections of different diameters, the pass-through opening of thenarrowed region of the tubular extension approximately equals the outerdiameter of that section of the shaft having the smaller diameterthread. This enables initial centering of the free end of the fastenerin the narrowed region during pre-mounting, after which an inseparablepre-mounting becomes possible by means of one or more rotations.

In the tubular extension, the narrowed region of the pass-throughopening can be simply cylindrical. By so doing, as a practical matter, athread is cut or pressed into a corresponding core-boring of theinserted fastener. In principle, an appropriate thread-boring can alsobe made in advance in the region of the pass-through opening, althoughthis involves substantially higher manufacturing costs for the tubularextension.

The pass-through opening in the narrowed region of the tubular extensioncan also be non-round in cross-section, or else provided on its wallwith ribs, protrusions, burls, grooves, or the like. In that version,there sometimes exists no circumferentially closed mutual threadengagement, but that is also not necessary for certain applications.What must be assured is only that mutual axial displacement betweenfastener and tubular extension results from mutual relative rotationwith an advance corresponding to the thread engagement.

In the inventive method, it is proposed to first make, in the structureformed by insulating strips, or plates, sealing strips and possiblyadditional layers, a hole substantially equal to the outer diameter ofthe tubular extension, then to make a hole in the concrete substructurewhich matches the thread of the screw, or of a hole in a plug for screwinsertion. There the washer with its tubular extension and the screw areinserted and the screw is driven in to the expected penetration depth.In so doing, the screw forms a mating thread in the narrowed end regionof the extension, or engages a thread previously formed therein.Finally, if stronger pressure of the washer against the top-mostinsulating strip is needed, the washer together with its tubularextension, which is in cooperative engagement with the screw, is rotatedrelative to the screw.

By this process, optimum fastening is obtained not only in restorationsof existing roofing structures, but also in new construction. Butespecially in the renovation of a substructure whose thickness is notknown in advance, the above-described fastening element used with theinventive process is especially desirable. Even the making of the firsthole in the overall structure can already provide a kind of test hole,by means of which the overall thickness of the structure can bedetermined. Then, fastening elements can be used in which the length ofthe tubular extension and the length of the screw are coordinated. Alsooptimized is the ability to retroactively, i.e. after final setting ofthe fastener, to adjust the pressure of the washer by rotating itrelative to the fastener.

A further desirable feature of the method is that the uppermost edge ofthe opening, which is defined in the washer by its tubular extension,can be brought into cooperative relationship by means of a drive tool.Required is only appropriate friction between the tool and the washer,in order to effect a rotation thereof, and with it a drawing-together,or a loosening.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Additional inventive features and special advantages are explained inmore detail in the description which follows. There is shown by:

FIG. 1, a fastening element according to the invention, which shows incross-section the large-area washer with its tubular extension;

FIG. 2, a section through a roofing structure with applied fasteningelement;

FIG. 3 to FIG. 8, the consecutive individual method steps for producingattachment using a fastening element in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

The fastening element 1 serves to attach to a fixed substructure 6insulating strips 2 and possibly additional sealing strips 3 or, forexample, additional bituminous underlayers 4 or other substructurematerials 5. In the example shown, the fixed substructure 6 to which thewhole addition is to be ultimately attached, takes the form of a thinwalled concrete element.

The fastening element 1 consists of a large-area washer 7 having atubular extension 8 and a screw 9. Screw 9 is provided with a screw head10 and a shaft 11 which is provided with a thread over at least aportion of its length.

The tubular extension 8 has, at least over a large section of itslength, a central recess, with an internal cross-section sufficient forrotational reception and axial displacement of screw head 10. At the endremote from washer 7, a narrowed portion 12 is provided, but whichpermits passage of the shaft 11 of screw 9. However, shaft 11 can notpass slideably through the narrowed region 12 in the axial directionbecause the outer diameter DA of shaft 11 provided with the thread islarger than the free pass-through opening of narrowed region 12. Thismakes it possible for a mutual threaded engagement to exist betweenscrew 9 and the inner wall of the pass-through opening in the narrowedregion of the tubular extension.

Screw 9 has a thread over at least a major portion of the length of itsshaft. In order to achieve greater displacement opportunity between thescrew and the tubular extension 8, this thread preferably extends overthe entire length of shaft 11.

In the illustrated embodiment of the fastening element, there areprovided on shaft 11 of screw 9 two differently configured threadsections 13 and 14. These two thread sections 13 and 14 preferably havedifferent diameters, but the same thread pitch. This precludes relativemotion between screw 9 and tubular extension 8 during the initialsetting of the screw 9, i.e. during turning of screw 9 into thesubstructure 6. The tubular extension 8, and with it also the large-areawasher 7, remain in their initial positions until the final setting ofscrew 9. However, thereafter, additional drawing and pressing togetherof washer 7 is possible by rotating it together with its tubularextension.

A match to the materials into which they are to be driven, can beachieved by special configuration of the thread segments. Thus, in theproposed example, the thread section 14 with the smaller diameter at thefree end of shaft 11 should take the form of a double thread, in whichthe two thread sections have different outer diameters.

In the proposed embodiment, the two thread sections 13 and 14 withdifferent diameters are so conformed to the pass-through opening in thenarrowed region 12 of the tubular extension 8 that the outer diameter ofthe section of shaft 11 having the smaller diameter thread isapproximately equal to the cross-section of the pass-through opening inthe narrowed section 12. In this way, during pre-mounting of screw 9 intubular extension 8, the first thread section 14 can simply be pushedthrough the narrowed region 12, so that only the thread section 13engages the wall of the pass-through opening in narrowed region 12.

The pass-through opening in narrowed region 12 of the tubular extension8 is preferably cylindrical, the thread being formed by the driven-inscrew or else in advance during manufacture of tubular extension 8. Forthe narrowed region 12 of the pass-through opening variousconfigurations are also possible. Thus, the cross-section can be madeother than round, or there can be provided in the region of the wall ofthe pass-through opening ribs, protrusions, burls, grooves, or the like.To prevent relative axial sliding, mutual engagement with the tubularextension should take place by the thread of screw 9 or by a threadsection 13 of screw 9. Axial displacement is to be possible only byrotating the tubular extension relative to screw 9.

With reference to FIGS. 3-8, there will now be explained the inventivemethod for attaching insulating strips 2 and additional sealing strips 3to a fixed substructure 6 made of a thin concrete plate. In so doing, itwill be assumed that the screw 9 with its thread section 14 formed atits free end directly engages the substructure 6. It is also possible toprovide in the substructure a hole for a plug into which a screw iscaused to engage.

FIG. 3 shows the first step. In order to prevent the hole 15 in roofingstructures with bituminous coatings from adhering to the bore dust andoptional silicium, a spiral drill 16 is employed, with the drillingpreferably taking place without percussive effects. The hole 15 is madeso deep that the free end of the drill stops at the substructure 6.

FIG. 4 shows how the hole 18 in substructure 6 is made with a specialdrill rod 17. An optimum hole exists when the drill 19 no longerproduces a substantial advance or when a change in the sound of thepercussion drill 19 is noticeable. The larger diameter A of the drillrod comes to rest against and therefore abuts against the top surface ofthe substructure 6. The large-area washer with its tubular extension andthe screw, can then be inserted into the prepared hole 15 (FIG. 5).

The screw is driven in by means of a screwing element 20 connected to atorque-limited screwdriver which engages an engagement recess in head 10of screw 9. The driving-in continues far enough that the thread section14 in FIG. 1 penetrates completely into substructure 6, i.e. the screw 9is seated at the lower end of hole 18. By means of preliminarypulling-out attempts, it can be determined how great the torque is whichis necessary to timely shut off the torque-limited screwdriver.

In this manner, the fastening element 1 is properly seated and alarge-area washer normally bears firmly against the upper-most side ofthe complete structure to be fastened. As can be seen, particularly inFIGS. 7 and 8, it can still happen that the large-area washer 7 does notrest properly on the upper-most sealing strip 3, i.e. pre-tensioningagainst the top-most cover of the whole structure is either notachieved, or it is too slight. Therefore, there exists the additionaladvantage of the present invention, namely using rotation of thelarge-area washer 7 with its tubular extension 8 to draw extension 8inwardly in the axial direction by virtue of the threaded engagementwith screw 9, the rotating movement being performed long enough thatsufficient pre-tensioning occurs, and thereby causing bearing of thelarge-area washer 7 against sealing strip 3.

FIG. 7 shows the situation after the final setting of screw 9. Here itis proposed to form on screwing element 20, a special projection 21which can, for example—as shown in FIG. 8—be pushed forward into aninserted position. Special projection 21 has an added piece 22 which isgenerally conical and is provided with ribs. In this embodiment, theprojection 21 can be inserted a short distance into the outward endregion of the tubular extension 8, so that co-rotation results. Finalsetting of the fastening element takes place by downward movement oftubular extension 8 along thread section 13, so that the screw itself isled farther into the interior of tubular extension 8.

It is also quite possible to equip the upper end of the tubularextension 8 facing large-area washer 7 with a kind of attaching point orsome form of tool attachment. However, if the tubular extension is madeof plastic, contact with special projection 21 is sufficient to providethe friction needed for co-rotation.

In the fastening element according to the invention, the large-areawasher and tubular extension are preferably made in one piece from aplastic material. However, the washer and the tubular extension can alsobe made from other materials. Thus, it is possible to use a large-areawasher 7 of metal into which there is then inserted a kind of tubularextension having an appropriate collar or with some axially operativeconnection for mutual fixation of washer and tubular extension. Screw 9can also be made from various materials, including stainless materials.For attachment to a substructure consisting, for example, of metal orfoam concrete, screw 9 can also be provided with a self-boring orself-piercing point.

The essential feature of the invention, namely that the tubularextension and the screw 9 are in mutually threaded engagement, can beachieved with different configurations of the screw, of the tubularextension and of the large-area washer.

What is claimed is:
 1. Attaching element for attaching insulating stripsor plates and possibly additional sealing strips to a fixedsubstructure, consisting of a screw, which is provided with a threadover at least a portion of the length of its shaft and which has a screwhead, and a large-area washer with a tubular extension, in which theextension of the washer has an internal cross-section at least over alarge portion of its length sufficient for the rotatable reception andfor the axial displacement of the screw head, and which is narrowed atits end region remote from the washer for passage of the screw shaft,characterized in that the outer diameter (DA) of the shaft (11) of ascrew (9) provided with a thread is greater than the free pass-throughopening of the narrowed region (12) of the tubular extension (8), sothat the screw (9) and the tubular extension (8) in its narrowed region(12) are in operative connection by means of mutual threaded engagement,or can be brought into such operative connection by rotation of thescrew (9) into the pass-through opening.
 2. Attaching element accordingto claim 1, characterized in that the screw (9) is provided with athread over at least a large portion of the length of its shaft (11). 3.Attaching element according to claim 1, characterized in that the screw(9) is provided with a thread over the entire length of its shaft (11).4. Attaching element according to 1, characterized in that on shaft (11)two differently configured thread sections (13, 14) of the screw (9) areprovided.
 5. Attaching element according to claim 4, characterized inthat the two thread sections (13, 14) on shaft (11) of screw (9) havedifferent diameters but equal thread pitch.
 6. Attaching elementaccording to claim 5, characterized in that, for two thread sections(13, 14) of different diameters, the pass-through opening at thenarrowed region (12) of the tubular extension (8) is approximately equalto the outer diameter of section (14) of shaft (11) having the smallerdiameter thread.
 7. Attaching element according to one of claim 1,characterized in that the pass-through opening in the narrowed region(12) of tubular extension (8) is cylindrically shaped.
 8. Attachingelement for attaching insulating strips or plates and possiblyadditional sealing strips to a fixed substructure, consisting of ascrew, which is provided with a thread over at least a portion of thelength of its shaft and which has a screw head, and a large-area washerwith a tubular extension, in which the extension of the washer has aninternal cross-section at least over a large portion of its lengthsufficient for the rotatable reception and for the axial displacement ofthe screw head, and which is narrowed at its end region remote from thewasher for passage of the screw shaft, characterized in that the outerdiameter (DA) of the shaft (11) of a screw (9) provided with a thread isgreater than the free pass-through opening of the narrowed region (12)of the tubular extension (8), so that the screw (9) and the tubularextension (8) in its narrowed region (12) are in operative connection bymeans of mutual threaded engagement, or can be brought into suchoperative connection by rotation of the screw (9) into the pass-throughopening, in that on shaft (11) two differently configured threadsections (13, 14) of the screw (9) are provided, in that the two threadsections (13, 14) on shaft (11) of screw (9) have different diametersbut equal thread pitch, and in that the thread section (14) having thesmaller diameter at the free end region of shaft (11) of screw (9) isdouble threaded.
 9. Attaching element according to claim 8,characterized in that the threads of the double threaded section (14)have different outer diameters.
 10. Attaching element for attachinginsulating strips or plates and possibly additional sealing strips to afixed substructure, consisting of a screw, which is provided with athread over at least a portion of the length of its shaft and which hasa screw head, and a large-area washer with a tubular extension, in whichthe extension of the washer has an internal cross-section at least overa large portion of its length sufficient for the rotatable reception andfor the axial displacement of the screw head, and which is narrowed atits end region remote from the washer for passage of the screw shaft,characterized in that the outer diameter (DA) of the shaft (11) of ascrew (9) provided with a thread is greater than the free pass-throughopening of the narrowed region (12) of the tubular extension (8), sothat the screw (9) and the tubular extension (8) in its narrowed region(12) are in operative connection by means of mutual threaded engagement,or can be brought into such operative connection by rotation of thescrew (9) into the pass-through opening, and in that the pass-throughopening in narrowed region (12) of tubular extension (8) hascross-section adapted for such connection.
 11. The method of attachinginsulating strips or plates and possibly additional sealing strips orbituminous underlayers to a fixed substructure of thin concrete by meansof a fastening element consisting of a screw and a large-area washerhaving a tubular extension according to claim 1, characterized in thatthere is initially provided, in the structure consisting of insulatingstrips (2) or plates, sealing strips (3) and possibly additional layers(4, 5), a hole which is substantially equal to the outer diameter of thetubular extension (8), then producing, in the concrete substructure (6),a hole (18) which fits the thread of screw (9) or possibly a plug forinsertion of screw (9), after which washer (7) with tubular extension(8) and screw (9) are inserted and screw (9) is driven-in to itsintended penetration depth, whereby the screw forms an engaging threadin the narrowed end region (12) of extension (8), or else engages athread preformed therein, and finally, if a stronger drawing-togetherforce of washer (7) against the upper-most sealing strip (3) is needed,washer (7) together with tubular extension (8) which is in operativeconnection with the thread of screw (9) is rotated relative to screw(9).
 12. The method of claim 11, characterized in that the upper-mostedge of the opening formed in washer (7) by tubular extension (8) can bebrought into operative engagement by means of a driving tool.